A NEW GIGANTIC SAUROPOD FROM THE MIDDLE JURASSIC OF SHANSHAN,

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1 A NEW GIGANTIC SAUROPOD FROM THE MIDDLE JURASSIC OF SHANSHAN, XINJIANG AUTONOMOUS REGION, CHINA Authors: Wu W.H., Zhou C.F, Wings O., Sekyia T.*, Dong Z.M. Abstract:A new gigantic sauropod dinosaur, Xinjiangtitan shanshanesis gen. et sp. nov. is reported with preliminary description. It is well preserved in situ and discovered from the Middle Jurassic Qigu Formtion in Shanshan of Xinjiang for the first time. Xinjiangtitan is characterized by a ventral keel developed on the penultimated cervical centrum and formed a small semi-circular process under the distal articular facet, last two cervical vertebrae are particularly elongated (ratio length of the last two cervical vertebrae / length of femur and tibia is 0.63), sacricostal yoke excepting the first sacral rib, and exremely robust femur (ratio transverse width of the distal end / femur length is 0.33). Cladistic analysis places Xinjiangtitan as the sister group of Mamenchisaurus. Xinjiangtitan is definitely a new taxon of mamenchisaurid dinosaur. However, Xinjiangtitan developed several diplodocid-like characters: prominent ambiens process of pubis, relatively short hind limb and caudomedially developed fourth trochanter on femoral body. The total body length of Xinjiangtitan is calculated as meter. Keyword:Shanshan of Xinjiang; Xinjiangtitan shanshanesis; Middle Jurassic; Qigu Formation; Mamenchisauridae; Sauropoda INTRODUCTION Since the first theropod teeth found in the mesozoic deposits in Turpan Basin, Xinjiang Autonomous Region, China (Young and Sun, 1957), numerous vertebrate fossil records have been reported from this area. Several isolated bones and teeth (belong to sauropod, theropod, ankylosaur, and tutle), and an incomplete small theropod (Shanshanosaurus huoyanshanensis), were discovered in the Jurassic and Cretaceous deposits, by the team from the IVPP in (Dong, 1977). Later, a Late Jurassic sauropod, Hudiesaurus sinojapanorum, including a dorsal vertebra and a complete right forelimb, was found by the team from The Sino-Japan Silk Road dinosaur expedition in (Dong, 1997). And recently, more than 150 theropod footprints (Wings et al., 2007) and estimated more than 1000 turtles (Wings et al., 2012) were discoverted in the Middle Jurassic Shanjianfang Formation and Qigu Formation respectively. For the putative discoveries, a new excavation by the member of EPLENEA and PLM, started just from last year in the same area. Astonishingly, a complete postcranial skeleton of gigantic sauropod dinosaur was found, but in the Middle Jurassic Qiketai Formation. The 1

2 excavation of this specimen is still on-going. However, some characters represent this individual belongs to a new species of Eusauropoda. And this new specimen showing a close relationships with the Late Jurassic sauropod Mamenchisaurus, this may could help us to understand the palaeogeography and evolution of the sauropd in the Jurassic of Asia. Here, the authors would report a preliminary description and phylogenetic position of this specimen. Institutional abbreviations: EPLENEA, Key-Lab for Evolution of Past Life and Environment in Northeast Asia, Ministry of Education, Jilin University, China; IVPP, Institution of Vertebrate Paleontology and Paleoanthropology, Beijing, China; PLM, Paleontological Museum of Liaoning; ZDM, Zigong Dinosaur Museum, Sichuan, China. GIOGRAPHIC AND GIOLOGICAL SETTINGS The fossil site is approximately 30 km northeast of the Shanshan county, about 8 km south of the Qiketai Twon, in the Turpan Basin (fig 1). The Jurassic deposites are well exposed in Shanshan area, which are the Middle Jurassic Xishanyao Formation, Sanjianfang Formation, and Qiketai Formation, Late Jurassic Qigu Formation (but recently dated with Ma±1.4 Ma in the Junggar Basin: Wang and Gao, 2012), and Kalazha Formation (Chen, 1985; Dong, 1997). The new sauropod specimen is preserved in the Middle Jurassic Qiketai Formation, within the dark-red mudstone.the bone bed is about 95 cm thick, and almost dipping vertically to the southwest. Numerus bivalves fossils are associated with this sauropod specimen, with most of them are preserved in the top of the underlying green silt stone. Figure 1. Geographical location of the sauropod dinosaur found in Shanshan, Xinjiang Autonomous Region, China 2

3 SYSTEMTIC PALAEONTOLOGY Dinosauria Owen, 1842 Saurischia Seeley, 1887 Sauropoda Marsh, 1878 Eusauropoda Upchurch, 1995 Xinjiangtitan gen. nov. Xinjiangtitan shanshanesis gen. et sp. nov. Diagnosis An extremely large individual belongs to Eusauropoda, distinguished following diagnoses: a ventral keel developed on the penultimated cervical centrum and formed a small semi-circular process under the distal articular facet, last two cervical vertebrae are particularly elongated (ratio length of the last two cervical vertebrae / length of femur and tibia is 0.63), sacricostal yoke excepting the first sacral rib, and exremely robust femur (ratio transverse width of the distal end / femur length is 0.33). Holotype An almost complete postcranial skeleton preserved in situ: including two postalmost cervical centra, numerous isolated cervical ribs, articulated twelve dorsal vertebrae and numerous isolated dorsal ribs, five sacral vertebrae with sacricostal yoke, two proximalmost caudal centra, a left ilium, left and right pubes, a left ischium, a complete left femur, tibia and fibula, and a fourth (or fifth) metatarsal. The occurred bone bed map is shown in Figure 2. Ca1,Ca2:the 1 st,2 nd caudal vertebra;ce:cervical vertebra;ce.r:cervical ribs;d1,d6,d12:the 1 st, 6 th,12 th dorsal vertebra;d.r:dorsal ribs;l.fi:left fibula;l.fe:left femur;l.mt:left metatarsal;l.pu:left pubis;l.ti:left tibia;r.ish:right ischium;s1 S5:1 st,5 th sacral vertebra. Fig. 2 Burial condition of Xinjiangtitan shanshanesis gen. et sp. nov. Etymology: Xinjiang, shanshan, where the fossil was discovered. Type locality and horizon 3

4 Qiketai Town, Shanshan County, Xinjiang Uygur Autonomous Region, China. GPS co-ordinates: N ', E '. The Middle Jurassic Qigu Formation. DESCRIPTION AND COMPARISON Cervical vertebrae Two posteriormost cervical vertebrae are exposed their ventral and a part of the lateral sides in situ (fig. 3; fig 4). The centra are strongly opisthocoelous and constricted laterally at their proximal one-thirds. The lateral pneumatic fossae is developed. Differs from other sauropod dinosaurs, a ventral keel developed on the penultimated cervical centrum and formed a small semi-circular process under the distal articular facet. But the last cervical centrum lacks of ventral keel. The length ratio of the penultimate and the posteriormost centra is 1.4, similar to Omeisaurus tianfuensis (He et al., 1988), but larger than which in Mamenchisaurus (1.2: Young and Zhao, 1972; Ouyang and Ye, 2002). Numerous isolated cervical ribs are preserved in situ. The longest one is at least two meters long, and the cross section is sub-circular. A proximal part of the cervical rib is preserved near the second posteriormost cervical centra (fig. 5) Ce.r: cervical ribs; pa: parapophysis; p: pleurocoel; v.k: ventral keel. Fig. 3 the penultimate cervical vertebra in right lateral view 4

5 Fig. 4 ventral keel of the penultimate cervical vertebra in posterior view Ant.p: anterior process; Tub: tuberculum. Fig. 5 proximal part of left cervical rib in lateral view Dorsal vertebrae 12 dorsal centra are preserved in articulation and expose their ventral surface in situ. The neural arch and spins are hardly damaged and not preserved except two transverse processes of the 3rd and 4th dorsal vertebrae. The centrum articular surfaces are weakly opisthocoelous, the convexity of anterior and posterior articular surfaces are not so strongly convex or concaved, respectively. Contrary to the revised diagnosis of Mamenchisauridae proposed by Lü et al., (2008), the posterior dorsal centra are not fused each other. The camellate internal structure of the centrum is visible in the weathered part of the ventral surface. The openings are about 2 cm transverse widths and 6~9 cm anteroposterior length. The transverse process directs horizontally in the second to fourth dorsal vertebrae, however, those of Mamenchisaurus and Hudiesaurus turns ventrolaterally (Dong, 1997; Ouyang and Ye, 2002). The distal end of the transverse process sub-rectangular in SSQ1101 however, that of Hudiesaurus is rounded in dorsal half, and sub-triangular in the ventral half in lateral view (Dong, 1997: fig. 1B). The transverse process of Brachiosaurus and Giraffatitan (Taylor, 2009) are much elongated and expanded laterally than that of Xinjiangtitan. Dorsal ribs Numerous fragmentary dorsal ribs are preserved beside the dorsal and sacral vertebrae and 5

6 the pelvic girdle. There is a cylindrical long bone preserved near the 8th to 12th dorsal centra could be regarded as a proximal part of the dorsal rib. The cross-section is rounded and the proximal part has triangularly concaved area. There are numerous compressed fragmentary parts of the dorsal ribs, the maximum ratio of anteroposterior width to mediolateral thickness is more than 4.0. The one side is convex, and the other side is relatively flat. According to the other taxa, the former could be the lateral side, and the latter is the medial surface. Fig. 6 the 9 th dorsal vertebra in ventral view. Sacral vertebrae Five sacral centra are fused tightly each other (fig. 7). The ventral surface is convex transversely without any ventral keel or sulcus. The distal end of each sacral ribs are fused together and constitute a sacricostal yoke. In lateral view, the yoke is sigmoidal curved shape and the posterior end direct posterodorsally. Different from the other sauropods, the first sacral rib is excluded from the anterior end of the sacricostal yoke, and it could be one of the diagnoses of Xinjiangtitan. The sacral ribs are not so elongated laterally centrally to those of Brachiosaurus and Giraffatitan (Taylor, 2009). There is a concavity on the ventral surface of the lateral half of the posteriormost sacral rib, and at the just medial to this concavity, the ventral surface is concaved. Because this morphology is not visible in the other sauropod dinosaurs, it could be a diagnostic character of Xinjiangtitan. 6

7 Ca.1: the first caudal vertebra; D12, the 12 th dorsal vertebra; S.y: sacriocostal yoke; S1, S5: the 1 st,5 th sacral vertebra. Fig. 7 Sacral vertebrae in ventral view (A) and lateral view (B) Caudal vertebrae Two proximalmost caudal centra are exposed in articulation posterior to the fifth sacral centrum. The lateral surface and neural arch are not visible. Contrary to Omeisaurus (He et al., 1988), Shunosaurus (Zhang, 1988) and the other Jurassic eusaropod dinosaurs (Upchurch et al., 2004a), the articular surface is procoelous. In the Jurassic sauropod, mamenchisaurid dinosaurs has procoelous anterior caudal centra (Upchurch et al., 2004a; Sekiya, 2011); however, the convexity is relatively weaker than that of Mamenchisaurus (Young, 1954). The ventral surface is rounded and convex without any longitudinal sulcus or keel. There are several nutrient foramina on the ventral surface of the first caudal centrum. Pubis Both the left and right pubes are preserved and exposed their ventrolateral aspects. The pubic apron is flat, and the direction of the cross-section is parallel to that of the ischial articular surface. In mamenchisaurid dinosaurs, the pubic apron is twisted against the transverse section of the ischial articular surface. Dorsoventral expansion of the distal end of the pubic apron is absent in Xinjiangtitan shanshanensis, contrary to several eusauropods including Barapasaurus (Bandyopadhyay et al., 2010), Patagosaurus (Bonaparte, 1986) and Vulcanodon (Raath, 1972; Cooper, 1984). In Omeisaurus tianfuensis, the distal end of the pubic apron is not expanded mediolaterally as Xinjiangtitan shanshanesis whereas that of Chuanjiesaurus is more expanded than Xinjiangtitan shanshanesis (Sekiya, 2011). The anterior tip of the pubic apron is rounded distally in Omeisaurus maoianus (Tang et al., 2001). The ischial articular part is convex laterally and concaved medially. There could be no pubic foramen on lateral surface of the main body. The ischial articular surface is almost perpendicular to the longitudinal axis of the pubis, contrary to Apatosaurus ajax (Upchurch et al., 2004b). The ambiens process is prominent on the pubis. The ambiens process is not developed or quite small in other mamenchisaurid dinosaurs. 7

8 am.p: ambiens process; L.fi, left fibula; L.mt: left metatarsal; L.pu: left pubis; mat: matrix; R.ti:Right tibia. Fig. 8 Right pubis in anterior view;left tibia, fibula, and metatarsal in medial view. Ischium Only the main body of the right ischium is visible, but the distal shaft is still needed to be excavated from the matrix. There is a moderate convexity in the center of the lateral surface of the main body of the ischium. Femur A complete left femur is preserved and its anterior, medial and lateral surfaces are exposed. The proximal end is expanded anteroposteriorly, the ratio of the anteroposterior thickness to the length of femur is quite larger than the other sauropods (0.18). The transverse cross-section of the mid shaft represent sub-circular, centrally to Chuanjiesaurus (Sekiya, 2011), M. hochuanensis (Ye et al., 2001), Brachiosaurus (Taylor, 2009). The distal end of the femur is significantly expanded mediolaterally and anteroposteriorly. The tibial condyle directs posteromedially, fit into the synapomorphy of Mamenchisaurus proposed by Wilson (2005). 8

9 4th.tr: fourth trochanter; ti.con: tibial condyle; mat: matrix. Fig. 9 left femur in medial view Tibia A complete left tibia is preserved in the almost natural articulated position beside the distal end of the left femur. The proximal end is semicircular in cross-section; the anterior margin is rounded and the posterior rim is relatively straight. Its long axis directs anterolaterally with 40 angle against the transverse axis of the distal articular surface of the tibia. The central part of the proximal articular surface of the tibia is moderately concaved. There are numerous small projections on the proximal articular surface of the tibia, which could be the attachment surface for the cartilage, and the projections at the anterior to the medial rim are larger than the lateral ones. The middle shaft is elliptical in cross-section, and the long axis is more twisted than the proximal end with 60 angle against the distal end. The distal end has concavity for attachment with the astragalus at the lateral margin; however, the astragalus is not found at present. The length ratio of tibia to femur is 0.59, represents average value in Eusauropoda (He et al., 1988; Ouyang and Ye, 2002; Sekiya, 2011). Fibula A rod-like long bone is preserved accompanied with the tibia, based on the preserved situation, it could be identified as the left fibula. Only the middle part and medial half of the distal part is visible in situ. The transverse cross-section seems elliptical. The distal end is expanded 9

10 mediolaterally at least two times of the minimum transverse width of the mid-shaft. Metatarsal A fourth or fifth metatarsal is preserved in the immediately below the tibia. The proximal articular surface is rugose and convex. The middle part is constricted dorsoventrally and mediolaterally. The distal articular surface is much smaller than the proximal one. Table 1. Measurements of the axial skeletons (in mm). Abbreviations: CL, centrum length; *, include the anterior articular ball of the centrum; **, except the anterior articular ball of the centrum; WAC,; WPC, width of the posterior articular surface of the centrum; MWC, minimum width of the centrum; Ce.p1, posteriormost cervical vertebra, in mm. Ce.p2 Ce.p1 D1 D2 D3 D4 D5 D6 D7 D8 D9 D10 D11 D12 CL 1040 * 690 ** 365 ** 290 ** 265 ** 255 ** Total ** 230 ** S1 S2 S3 S4 S5 Ca1 Ca2 CL Transverse width of the anterior articular surface of the centrum of S3 195 Distance between center of the ventral surface of the first sacral 260 centrum to the lateral end of the sacricostal yoke Anteroposterior length of the right sacricostal yoke 730 Table 2. Measurements of the appendicular skeletons (in mm). In mm Notes Left ilium Dorsoventral height of the ilium 850 Dorsoventral height of the preacetabular 380 process Anteroposterior length of the preacetabular

11 process Right pubis Anteroposterior length 1045 Anteroposterior width of the iliac articular 250 surface Transverse width of the ischial articular surface 360 Left femur Length of the left femur 1650 Anteroposterior width of the proximal end 290 Transverse width of the mid-shaft 260 Anteroposterior width of the mid-shaft 180 Circumference of the mid-shaft?800 Calculated from the circumference of the anterior half Distal width of left femur 550 Circumference of femur 760 Temporally calculated from the distal half. More preparation is needed Tibia Length of the left tibia 980 Transverse width of the proximal end 375 Anteroposterior width of the proximal end 295 Transverse width of the mid-shaft 203 Anteroposterior width of the mid-shaft 105 Transverse width of the distal end 290 Fibula Transverse width of the mid-shaht Transverse width of the distal end 11

12 DISCUSSION Body length estimation Although the fossil excavation is still keeping undergoing, here the authors would like to estimate the body length of Xinjiangtitan shanshanesis, based on the temporally exposed materials. Based on the length ratio of total length of dorsal centra and estimated total body length of M. hochuanensis (hotolype: Young and Zhao, 1972) and M. youngi (Ouyang and Ye, 2002), The total body length of Xinjiangtitan shanshanesis is estimated as 32.5 meters long. However, the distinguish feature of this taxon is especially elongated cervical vertebra. Therefore, in order to estimate more reliable body length, further excavation and preparation of the fossil specimens are required. 12

13 Table 3. Relative measurements of Xinjiangtitan shanshanesis and closely related taxa. estimated total body length neck length penultima te cervical length (p.ce.l) Posterior -most cervical length Total length of dorsal centra (TLD) femur length (FL) distal width (DW) ratio of DW to FL ratio of p.ce.l to FL ratio of TLD to FL tibia length (TL) ratio of TL to FL references XXXsaurus 32.5? Omeisaurus (T5701) M. hochuanensis (holotype) M. hochuanensis (ZDM0126) M. youngi (ZDM0083) Chua njie-s aurus Holotyp e Referred specime n ? 0.415??? 0.86?? 6+?? <0.4?????? ????? ?? ? 5.5+??? ???? He et al., (1988) Young & Zhao (1972) Ye et al., (2001) Ouyang and Ye, (2002) Sekiya (2011) 13

14 Body mass estimation Mamenchisaurus hochuanensis is estimated as 14 to 18 tons. Because the femur length of the new sauropod is 1.4 times longer than M. hochuanensis, the weight of that is estimated as 36 to 46 tons. Brachiosaurus altithorax is estimated as 43.9 tons based on the long bone circumference (Foster 2007). Jurassic paleobiological fauna of Shanshan area In the fossil locality of Shanshan area, numerous bivalve shells, turtle bones and two isolated theropod teeth are found accompanying the Xinjiangtitan shanshanesis Phylogenetic analysis Dataset and method The phylogenetic position of Xinjiangtitan shanshanensis is analyzed by PAUP 4.0 beta 10 with the revised datasets based on the character description and data matrix of Harris (2006). Based on the original settings of Harris (2006), the following characters are considered as ordered: #6, 14, 89, 93, 284 and 324. The revised data matrix is composed of 32 operational taxonomy units (OTUs) which is composed of original OTUs of Harris (2006) and two additional taxa, Xinjiangtitan shanshanesis and Bellusaurus from Jurassic of Xinjiang. The outgroup are Theropoda and Prosauropoda. The present data matrix is modified based on the currently revised codings of Barapasaurus and Brachiosaurus by Nair and Salisbury (2012) and Taylor (2009), respectively. Furthermore, following codings are revised: Omeisaurus: #156 is modified from 2 to 1, Result and interpretations 1,000 repricates of heuristic search generated 9 most parsimonious trees (MPTs) with 837 steps of tree length (TL), consistency index (CI) = 0.493, retention index (RI) = The strict consensus tree is showed in Figure # with 10,000 repricated bootstrap values of main clades. The synapomorphies of major taxa analyzed by ACTRAN and DELTRAN are shown in Table 4. The strict consensus tree represents Xinjiangtitan shanshanesis is a sister taxon of Mamenchisaurus. This relationship is not supported robustly, i.e., the bootstrap value is 21.8% and extra step to collapse this clade (decay index) is only 1. Further excavation and preparation is required to achieve more advanced analysis. Table 4. The synapomorphies (CI = 1.000) and bootstrap suport values of major taxa. Astarisk (*) 14

15 represent the inambiguous states. node Taxon ACTRAN DELTRAN bootstrap 1 Sauropoda 2 Eusauropoda 13:1, 17:1, 20:2, 39:1, 41:1, 45:1, 46:1, 50:1, 53:1, 54:1, 55:1, 58:1, 62:1, 85:1, 89:1, 90:1, 93:1, 99:1, 107:1, 165:1, 180:1*, 206:1, 227:1*, 234:1*, 244:1, 247:1*, 254:1, 256:1, 259:1, 263:1*, 265:1, 275:1*, 286:1*, 295:1, 303:1*, 308:1*, 324:1*, 325:1*, 328:1* 267:1*, 298:1, 320:1*, 321:1*, 322:1*, 327:1*, 329:1* 3 Neosauropoda 158:1*, 258:1*, 264:1* 4 Diplodocoidea 5 Fragellicaudata 6 Diplodocidae 1:3*, 8:1, 22:1, 38:2, 48:1, 49:1*, 56:1, 58:2, 59:1, 76:1*, 93:2*, 106:1, 194:2*, 319:1, 323:1 10:1*, 50:1*(reversed), 80:1*, 163:2, 173:1*, 174:1, 266:1* 24:1*, 78:1*, 135:1*, 181:1*, 182:1*, 192:1* :1*, 227:1*, 234:1*, 247:1*, 263:1*, 275:1*, 286:1*, 303:1*, 308:1*, 325:1*, 328:1* 13:1, 17:1, 20:2, 39:1, 41:1, 45:1, 46:1, 50:2, 53:1, 54:1, 58:1, 62:1, 85:1, 90:1, 93:1, 99:1, 107:1, 165:1, 206:1, 244:1, 254:1, 256:1, 259:1, 265:1, 267:1*, 295:1, 320:1*, 321:1*, 322:1*, 324:1, 327:1*, 329:1* 21:1, 43:1, 61:1, 158:1*, 175:1, 176:1, 245:1, 258:1*, 264:1*, 324:2 1"3*, 49:1*, 76:1*, 93:2*, 194:2* 8:1, 10:1*, 38:2, 50:1*(reversed), 80:1*, 106:1, 173:1*, 266:1*, 319:1 22:1, 24:1*, 48:1, 56:1, 58:2, 59:1, 78:1*, 135:1*, 163:2, 174:1, 181:1*, 182:1*, 192:1*, 323:1 decay index 100.0% % % % % % 2 7 Macronaria none 83:1 12.4% 1

16 8 Titanosauriformes 9 Somphospondyli 10 Titanosauria CONCLUSION 89:2, 134:1, 189:1*, 251:1*, 257:1*, 285:1*285:1* 72:2, 75:1, 202:1, 223:1, 232:1*, 254:2, 274:1 1:2, 20:1 (reversed), 47:1, 60:1*, 228:1*, 294:1* 189:1*, 251:1*, 257:1*, 285:1* 32.1% 1 232:1* 52.6% 1 60:1*, 72:2, 202:1, 274:1, 294:1* 84.5% 4 An extremely huge sauropod, Xinjiangtitan dongi gen. et sp. nov. is reported with preliminary description and phylogenetic analysis. It is distinguished from the other taxa based on its relative elongation of penultimate cervical centra, extremely robust femur, unique yoke and pubis structures. The phylogenetic analysis represents Xinjiangtitan belongs Eusauropoda, positioned at a sister taxon of Mamenchisaurus with weak support. Although further excavation is needed, the total body length of Xinjiangtitan is calculated as 32.5 meter, temporally. ACKNOWLEDGEMENTS The authors thank Mr. Yang (Geological Bureau of Xinjiang?) for all the trouble he went to in accommodating and financial supports.elena Craus Daniel Gaburie and staff of LPM and EPLENEA contributed largely during the excavation and preparation. REFERENCES Bandyopadhyay, S., D. D. Gillette, and S. Ray Osteology of Barapasaurus tagorei (Dinosauria: Sauropoda) from the Early Jurassic of India. Palaeontology 53: Bonaparte, J. F Les Dinosaures (Carnosaures, Allosauridés, Sauropodes, Cétiosauridés) du Jurassique Moyen de Cerro Cóndor (Chu but, Argentine). Annuales de Paléontologie (Vertébrés-Invertébrés) 72: Chen, Z. ed., Explanatory notes on the geological map of Xinjiang Uygur Autonomous Region, China: Beijing, China, Geological Publishing House, 82 p. (in Chinese with English abstract) Cooper, M. R A reassessment of Vulcanodon karibaensis Raath (Dinosauria: Saurischia) and the origin of the Sauropoda. Palaeontologia Africana 25:

17 Dong, Z On the dinosaurian remains from Turpan, Xinjiang. Vertebrata PalAsiatica 15: Dong, Z A gigantic sauropod (Hudiesaurus sinojaponorum gen. et sp. nov.) from the Turpan Basin, China; pp in D. Zhiming (ed.), Sino-Japanese Silk Road Dinosaur Expedition. China Ocean Press, Beijing. Harris, J. D The significance of Suuwassea emilieae (Dinosauria: Sauropoda) for Flagellicaudatan in trapelationships and evolution. Journal of Systematic Palaeontology 4: He, X., K. Li, and K. Cai Sauropod dinosaur (2) Omeisaurus tianfuensis. The Middle Jurassic dinosaurian fauna from Dashanpu, Zigong, Sichuan 4:143. Lü, J., T. Li, S. Zhong, Q. Ji, and S. Li A new Mamenchisaurid dinosaur from the Middle Jurassic of Yuanmou, Yunnan Province, China. Acta Geologica Sinica (English Edition) 82: Nair, J. P., and S. W. Salisbury New anatomical information on Rhoetosaurus vrownei Longman, 1926, a grabisaurian sauropodomorph dinosaur from the Middle Jurassic of Queensland, australia. Journal of Vertebrate Paleontology 32: Ouyang, H., and Y. Ye The first Mamenchisaurian skeleton with complete skull Mamenchisaurus youngi. Sichuan Science Technology Press, Chengdu, 111 pp. Raath, M. A Fossil vertebrate studies in Rhodesia: an new dinosaur (Reptilia: Saurischia) from near the Trias-Jurassic boundary. Arnoldia (Rhodesia) 30:1 37. Sekiya, T Re-examination of Chuanjiesaurus anaensis (Dinosauria: Sauropoda) from the Middle Jurassic Chuanjie Formation, Lufeng County, Yunnan Province, southwest China. Memoir of the Fukui Prefectural Dinosaur Museum 10:1 54. Tang, F., X. Jin, X. Kang, and G. Zhang Omeisaurus maoianus: A Complete Sauropoda from Jingyan, Sichuan.128. Taylor, M. P A re-evaluation of Brachisaurus altithorax Riggs 1903 (Dinosauria, Sauropoda) and its generic separation from Giraffatitan brancai (Janensch 1914). Journal of Vertebrate Paleontology 29: Upchurch, P The evolutionary history of sauropod dinosaurs. Philosophical Transactions: Biological Sciences 349:

18 Upchurch, P., P. M. Barrett, and P. Dodson. 2004a. Sauropoda; pp in D. B. Weishampel, P. Dodson, and H. Osmolska (eds.), The Dinosauria (Second Edition). University of California Press, Berkley. Upchurch, P., Y. Tomida, and P. M. Barrett. 2004b. A new specimen of Apatosaurus ajax (Sauropoda: Diplodocidae) from the Morrison Formation (Upper Jurassic) of Wyoming, USA. National Science Museum Monographs 26:108pp. Wang S. E., Gao L. Z SHRIMP U-Pb dating of zircons from tuff of Jurassic Qigu Formation in Junggar Basin, Xinjiang. Geol Bull China, 31(4): Wilson, J. A Integrating ichnofossil and body fossil records to estimate locomotor posture and spatiotemporal distribution of early sauropod dinosaurs: a stratocladistic approach. Paleobiology 31: Ye, Y., H. Ouyang, and Q. Fu New material of Mamenchisaurus hochuanensis from Zigong, Sizhuan. Vertebrata PalAsiatica 39: Young, C. C On a new sauropod from Yiping, Szechuan, China. Scientia Sinica 3: Young, C. C., and X. Zhao Mamenchisaurus hochuanensis. Institute of Vertebrate Paleontology and Paleoanthropology monograph Series I 8:30. Zhang, Y Sauropod dinosaur (I) Shunosaurus, The Middle Jurassic dinosaurian fauna from Dashanpu, Zigong, Sichuan, Volume 3. Sichuan Publishing House of Science and Technology, Chengdu, 89 pp. 18